1. Field of the Invention
The present invention is related to a printed wiring board having a pad formed on the upper-surface side of a resin insulation layer to mount an electronic component such as a semiconductor element, a conductive circuit (including an external connection terminal) formed on the lower-surface side of the resin insulation layer to be connected to an external substrate, and a via conductor formed in the resin insulation layer to connect the pad and the external connection terminal. The present invention is also related to a method for manufacturing such a printed wiring board.
2. Discussion of the Background
Japanese Laid-Open Patent Publication 2000-323613 describes a printed wiring board (multilayer substrate) formed by alternately laminating a resin insulation layer and a conductive layer without using a core substrate. In the multilayer substrate of Japanese Laid-Open Patent Publication 2000-323613, pads for a semiconductor element are formed on the upper-surface side, and pads for external connection terminals are formed on the lower-surface side. The pads for a semiconductor element are embedded in the outermost insulation layer on the upper-surface side. The surfaces of the pads for a semiconductor element are set at the same level as the outermost-layer surface, or are recessed from the outermost-layer surface. On the other hand, the pads for external connection terminals on the lower-surface side are formed on the outermost insulation layer at the lower-surface side. The contents of this publication are incorporated herein by reference in their entirety.